Light emitting devices, such as LED and LD, that emit light of shorter wavelengths, e.g. about 375 nm or less, are required to provide a white LED as a substitute for the mercury lamp or to meet the requirement to improve the precision of photolithography process.
As a GaN-based light emitting device, on the other hand, many light emitting devices that include the active layer of InGaN are widely demanded for the reason of high light emitting efficiency. In order to have the light emitting devices that use InGaN as the active layer emit light of such short wavelengths as described above, it is necessary to decrease the concentration of In therein. However, as the concentration of In becomes lower, light emission efficiency of InGaN becomes lower with the threshold current increasing, thus resulting in such a problem as the threshold becomes especially high at wavelengths of laser oscillation not longer than 380 nm.